OBJECTIVETo investigate the effects and mechanism of cytokine-induced killer (CIK) cells in reversing multidrug resistance (MDR) and increasing intracellular concentration of adriamycin (ADR) in the K562/ADR cells.

METHODSPeripheral mononuclear cells (MNCs) were isolated from healthy donors and cultured with combined cytokines to generate CIK. The changes of cell phenotype and cytokines secretion of CIK were determined. K562/ADR cells were divided into three groups: ADR in combination CIK (group I), CIK alone (group II) and ADR alone (group III). The viability and proliferation of K562/ADR cells were assayed by MTT assay, the intracellular concentration of ADR and the expression of P-glycoproteins (P-gp) in K562/ADR cells by FCM.

RESULTSThe cytotoxicity of ADR in group I was higher than that in group II (P < 0.05). The cytotoxicity was increased with the E/T ratio increasing (P < 0.05) but had no relation with the concentration of ADR in group I (P > 0.05). The expression of P-gp was declined in group I and group II (P > 0.05). The intracellular concentration of ADR in group I was higher than that in group II (P < 0.05), and had no relation with the ADR concentration (P > 0.05).

CONCLUSIONPre-treatment with CIK can increase the cytotoxicity and the intracellular concentration of ADR and decrease the expression of P-gp in K562/ADR cells in the ADR and CIK combination group. Acute leukemia patients would be most likely to benefit from the combination of chemotherapy and CIK therapy.